Interactive scripts for haptic virtual environments

When virtual environments reach the level of complexity required to accomplish significant tasks, such as educating students or playing games, they are based on well-written scripts. Scripts, even for continuous, real-time environments, can be written as a sequence of turns between the environment and the user. An interactive script is structured as a main plot line and alternative branches with cross references, terminations, and loops. Efficient script design requires empirical testing during development. As environments reach a sufficient level of complexity, they may be controlled by a variety of relatively independent scripts.